Process of extracting constituents of hydrocarbon liquids



Feb. 16, 1943. a M. DONS ETAL PROCESS OF EXTRACTING CONSTITUENTS OF HYDROGARBON LIQUIDS Filed May 1, 1940 2 Sheets-Sheet 1 w 7 1 8 A W l \g n 3 q a LEE 1 z i M f a A 5. am

INVENTORS BY AURO avuwg m a ATTORNEY.

E. M. DONS ET AL Feb. 16,1943.

PROCESS OF EXTRAGTING CONSTITUENTS OF HYDROCARBON LIQUIDS Filed May 1, 1940 2 Sheets-Sheet 2 B A B A 5 VA 5 Patented Feb. 16, 1943 -PROCESS F EXTRACTING OONSTITUENTS 0F HYDROOABBON LIQUIDS Eddie M. Dons and Oswald G. Mauro, Tulsa, Okla, assignors to Mid-Continent Petroleum Corporation, Tulsa,

. Delaware Okla", a corporation of Application May 1, 1940, Serial No. 332,736-

8 Claims.

This invention relates to processes of extracting hydrocarbon liquids, and more particularly to countercurrent processes wherein selective solvents are employed to extract selected constituents. For example, the invention may be employed in refining gasoline, kerosene, lubricating oils, fuel oils, etc., to separate paraflinic hydrocarbons from naphthenic and aromatic compounds, or to separate aromatic compounds from naphthenic compounds.

The important results of the new process include extremely high emciency in the extracting operation, economy in the relatively small quantity of solvent required per barrel of oil treated, high capacity as measured in barrels per day, and low operating costs. We have shown how to accomplish all of these results while obtaining substantial saving in the initial cost of the extracting apparatus, as well as the advantage of having a simple extracting system located in a relatively small space.

An extremely high degree of efllciency is ob tained by deliberately dividing counterflowing streams of solutions into numerous small streams, or films. which are subjected to numerous mixing, scrubbing and settling operaticns. In the preferred form of the invention, the small counterflowing streams intersect and mix with each other at frequent intervals, and

the mixed constituents are free to settle at points between the adjacent mixing zones.

The frequent repetition of the mixing, scrubbing and settling operations, occurring in relatively small portions of the solvent and charging stock, produces a very remarkable increase in the efliciency of an extracting system, and we have found that the present invention also greatly increases the capacity of throughput per day. In other words, for an apparatus having a given volumetric content of oil and solvent, the capacity as measured in .barrels per day will be" relatively high. Consequently, very substantial commercial advantages appear in relatively low initial cost of the system, the relatively small space required for this compact system, and the increase in efliciency due to the unique manner in which the counterflowing streams are With the foregoing and other objects in view, the invention comprises the novel process hereinafter more specifically described and shown in the accompanying drawings, which illustrate one form of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications within the scope of the claims hereunto appended.

Briefly stated, the preferred form of the invention is a'countercurrent process including the steps oftransmitting continuous streams of selective solvent and hydrocarbon liquid into different portions of an extracting chamber, dividing resultant solutions into annular rising and descending streams at various elevations in said chamber, the annular rising streams formed at eachof said elevations being separated from each other, and causing annular descending streams of said solutions to flow across and descend between separated rising streams at each of said elevations.

divided and transmitted through the numerous mixing and settling zones. The operating costs are also relatively low, as it is not necessary to employ numerous mechanically operated mixing devices, and the high efliciency of the mixin and settling operations enables the process to be carried out with a relatively small quantity of solvent per barrel of oil treated. a

Fig. 1 is a diagrammatical vertical section, drawn to a small scale showing an extracting chamber equipped with numerous concentric baffle rings, arranged to repeatedly divide the rising Fig. 3 is a diagrammatical vertical section drawn to a still larger scale, and showing conditions which exist near the upper and lower ends of the extracting chamber, the intermediate portions of the system being broken away.

As a simple illustration of a suitable extracting chamber, we have shown an upright cylindrical chamber, or column, 4 provided with an inlet conductor 5 for the selective solvent, and a lower inlet conductor 6 for the charging stock to be treated in the system. These inlet conductors may be equipped with pumps I and 8 to force continuous streams of the solvent and charging oil into the extracting chamber. To aid in distributing the solvent, the inner end of the solvent conductor 5 may be provided with a flaring nozzle 9 having an annular outlet at its periphery. The inner end of the lower conductor 6 is likewise equipped with a flaring nozzle it having an annular outlet.

When the system is operating, the chamber 4 is approximately filled with liquid, and a continuous stream of the heavy extract is discharged through a pipe leading from the lower through a pipe leading from the upper portion of said chamber, and equipped with a regulating valve H. A flaring deflector I! may be located in the'upper portion-of the chamber 4 to receive the raflinate which flows over the inner edge of said deflector and passes tothe discharge pipe |3.

In the system shown by Fig. 1, a relatively heavy selective solvent enters the upper portion of the extracting chamber and tends to flow downwardly, while the charging oil entering the lower portion of said chamber is relatively light,-

or it has relatively light constituents tending to rise from the inlet nozzle III. This results in a counterflow wherein the descending solvent enters into the oil so as to select and dissolve the constituents to be extracted from the oil, the resultant heavy extract solution being discharged at the bottom through the pipe whilethe lighter constituents rise to the top and flow out through the discharge pipe l3. However, it is to be understood that in some cases, the

selective solvent will be lighter than the charging oil, and that the solvent will then rise through the oil. For convenience in the following description, and without limiting the invention to these conditions, we will assume that the selective solvent is relatively heavy, and that it is employed to extract naphthenic and aromatic compounds from paraiflnic constituents of petroleum lubricating oil stocks. We may also assume that the selective solvent is dichlorethyl ether (chlorex), although any other suitable solvent may'be employed.

In the use of selective solvents, one of the outstanding objects is to thoroughly mix the solvent with the charging stock, so that the solvent will eiiectively dissolve all of the constituents to be extracted. In actual practice, this involves time and repeated mixing and settling operations intended to expose all parts of the charging stock to the solvent, and permit separation of the resultant solutions.

We divide the oil and solvent into numerous relatively small streams and cause these streams preferably lie in the same horizontal plane, but

they are separated from each other to provide annular spaces, and they are preferably, but not essentially, concentric with each other. To avoid unnecessary confusion, we have not shown supports for the rings, but it will be understood that the members of each group can be united in any suitable manner and attached to the chamber 4.

We will now refer to preliminary distributing zones wherein the incoming streams of solvent and charging stock advance step by step from one plane to another, while each incoming stream spreads into a series of annular streams, the number of said annular streams being pro gressively increased.-

For example, at the lower portion of Fig. 3, the preliminary distribution of the rising material is indicated by dotted lines. An annular stream of incoming charging stock rises from the periphery of the spreading nozzle ID to the middle portion of a ring l8 where it spreads toto flow in intersecting paths, thereby exposing flne streams of the oil to the selective action of the counter-flowing solvent, so as to permit free and positiveextraction of the constituents to be removed from the oil. 7

To illustrate a suitable means for carrying out our method of mixing and settling the 'counterof the chamber 4, an intermediate ring I! surrounded by said outer ring it, and an inner ring. I. surrounded by said intermediate ring. Each' group B consists of'an outer ring l9 separated from the inner face of the chamber B,-

an intermediate ring 20 surrounded by said outer ring l9, and a central disk 2| surrounded by said intermediate ring 20.

ward the inner and outer edges of said ring I8. As a consequence, the rising material is divided into two concentric annular streams, one rising from the outer edge of ring I8 while the other rises from the inner edge. The inner annular stream contacts with a central disk 2| where it spreads to a larger diameter and rises from the circular. outer edge of said disk 2| to a higher ring l8. Another spreading, or flattening, occurs at the bottom face of said higher ring I8, and we may assume that most of the liquid just referred to will rise as an annular stream from the inner edge of said higher ring II to the still higher central disk 2|. This disk 2| forms part of the .lowest completegroup B.

Attention is now directed to the conditions beginning at the outer edge of the lowermost ring |8' in Fig. 3.- Thevannular stream rising from this outer edge strikes the bottom of a higher ring 20' where it is flattened and'divided'into two concentric annularstreams rising from the inner and outer edges of said ring 20', the inner annular stream being transmitted to the bottom of the higher ring l8, while the companion outer stream rises in an annular course from the outer edge of said ring 20' to the bottom face of a higher ring II. This rising stream is flattened on said bottom face and divided into two concentric annular streams which rise from the inner and outer edges of said ring the inner stream being delivered to the bottom of a ring 20 while the outer stream is transmitted to the bottom of a ring l9. These rings l9 and 20 are associated with the disk 2| in the same plane to form the lowest complete group B.

' We 'will'now endeavor to approximately describe conditions of the rising material at the 1 lowest complete group B, and it will be understood that similar conditions exist at each of the higher groups B. Throughout Fig. 3, the flow or the rising material is suggested-by dotted lines, while theilow 0f descending material is suggested by the relatively thin full lines. At the-lowest sroup B. the outer ring ll receives an annular rising stream'from the outer edge of the lower ring W, said rising stream being flattened on the bottom face of ring II and divided into two annular streams which rise from the inner and outer edges of the ring it to the next adjacent higher rings It and "of group A. The annular stream rising fromthe outer edge of the last mentioned ring it is flattened on'the next higher ring I. and contracted into an annular stream of smaller diameter which rises from the inner edge of the ring I! to the bottom of a still higher ring it. Again referring to the ring I. in the lowest complete group B, .the annular stream rising from the inner edge of said ring I! is fiattened'on the bottom of a higher ring i1, and most ofthis ma terial will rise in the form of an annular stream from the outer edge of said ring I! to the next higher ring I. Still referring to the lowest complete group B, it 'will be observed that two annular streams rise from the inner and outer edges of the ring 20 to the next higher rings i1 and it where they are permitted to flowtoward each other and rise to the next higher ring 20. The central disk 2| of the lowest complete group B receives an annular stream from the inner edge of a ring it, said stream being flattened on the bottom of said central disk where it spreads to a larger diameter and then rises from the outer edge of the disk to the next higher ring it in one of the A groups.

After passing through all oLthe numerous alternating groups A andB, the lightest components of the rising material are eventually discharged from said groups in the form of concen-- tric annular streams, as suggested by dotted lines atthe upper portion of Fig. 3. Assuming that the charging stock is a lubricating 011 stock, and that the object is to extract naphthenic compounds from paraffinic hydrocarbons, the light-.

annular streams including a stream between the rings l8 and II of said group A, another annular stream between the rings l1 and I8 and a stream descending through the central opening in said ring it. The descending heavy solvent gradually advances through the numerous groups A and B. so as to eflectively mix with and dissolve naphthenic constituents in the rising streams.

- the solutions intersect and descend between separated annular rising streams at each of said elevations. The mixed light and heavy solutions est material will :be the paraffinic oil containing i.

a small percentage of the extracting solvent.

The incoming continuous stream of relatively heavy selective solvent is admitted through the spreading nozzle 9 at the ripper portion of Fig. 3, and discharged in an annular stream from the periphery of said nozzle. The flow of this heavy descending solvent is suggested by the ap-'" proximately diamond-shaped full lines in Fig. 3. However, it is to be understood that this illustration of the flow is merely a diagrammatical aid in pointing out the general directions of theflow, and that we are not attempting to illustrate or describe all of the details of the highly complex tortuous currents and countercurrents due to the.

numerous mixing and settling operations which occur throughout the system.

The preliminary distribution of the incoming solvent at the upper'portion of Fig; 3 is similar to the distribution previously described in referring to the incoming charging stock. It will be understood that the solvent is gradually divided into a series of concentric annular streams as it flows downwardly from the nozzle 9 at the upper portion of Fig. 3 to the highest complete group of baflles B. At this highest group B, a large annular stream of solvent flows downwardly around the outer edge of the ring IS; a solvent stream of smaller diameter descends between the rings i9 and 20, and a stream of still smaller diameter descends betwen the ring 20 and disk are allowed to settle in approximately concentric annular settling zones between the groups of batfles .A and B. The descending streams of heavy constituents spread and flow laterally toward opposite sides of each of the annular settling zones above the bailles II, IO, N, 20 and 2|, so as to divide each of these annular streams into two lateral streams of different diameters, which flow across two approximately concentric rising streams. The descending lateral streams passing irom one settling zone are merged with aproximately concentric lateral streams from other settling zones at the same elevation. It will also be observed that each: of said descending lateral streams is transmitted across one of the rising streams before it merges into the lateral stream from another settling zone.

In extracting naphthenic compounds from lubricating oil stocks, the relatively light .paraillnic solutions will readily flatten on the bottom faces of thebailles, thereby producing relatively thin films approximately as indicated by dotted lines in Fig. 3. These films are surrounded by and in direct contact with the counterflowing solvent, and they are effectively scrubbed by the annular solvent streams which flow across the numerous annular rising films.-

We claim:

1. In the art of using selective solvents to extract constituents of hydrocarbon liquids, the j 'countercurrent process which comprises transmitting continuous streams of the selective sol.- vent and hydrocarbon liquid into diflerent portions or an extracting chamber, dividing resultant solutions into approximately concentric 2|. Thereafter, the heavy solvent flows between i annular rising and descending streams at diilerent elevations in said extracting chamber, the annular rising streams formed at each of said elevations being of successively increasing diameters and separated from each other, and causing annular descending streams of said solutions to intersect and descend between separated rising streams of diflerent diameters at each of said elevations.

2. In the art of using selective solvents to extract constituents of hydrocarbon liquids, the countercurrent process which comprises transmitting continuous streams of the selective solvent and hydrocarbon liquid into different portions of. an extracting chamber, dividing resultant solutions into rising annular streams at different elevations in said extracting. chamber, a series'oi said rising annular streams formed at each or said elevations and the rising streams of each series being of diiierent diameters and approximately concentric witheach other, and

causing annular descending streams 01' said solutions to intersect and contact with approximately I concentric rising streams at each 01' said elevations. i

3. In the art of using selective solvents to extract constituents of hydrocarbon liquids, the countercurrent process which comprises transmitting continuous streams of the selective solvent and hydrocarbon liquid into diirerent porcausing annular descendingstreams of the solustreams toward .and away from. the centeroi said chamber asthey advance i'rom one of said elevations so as to convert the rising annular streams into. annular streams oi. diflerent diameters at the next higher elevation, and causing annular descending streams oi. solution to intersect and descend between separated annular streams'at each of said elevations.

6. In the art of using selective solvents to extract naphthenic compounds from lubricating oil stocks, the countercurrent process which comprises transmitting a continuous stream of the selective solvent into an extracting chamber while transmitting a continuous stream of lubricating oil stock .into a lower portion oi said chamber,.dividing .resultant solutions into numerousapproximatelyconcentric annular streams oi diflerent diameters'rising .at diflerent elevations in said extracting chamber. the

tions to intersect and descend betweenseparated rising annular streams at each of said elevations, allowing mixed light and heavy solutions to settle in annular zones between said elevations, and causing descending heavy constituents to flow laterally toward opposite sides of each oi. said annular fsettlingzones, so as to divide each of said annular descending streams into two lateral streams which flow across and mix with two of said separated rising annular streams. a W 4. In the art of using'selective-solvents to ex tract constituents of hydrocarbon liquids, the I streams; of the solvent and ,naphthenic comcountercurrent process which comprises trans mitting continuous streams of the selectivesolventand hydrocarbon liquid into diflerent portions of an extracting chamber, dividing resultant solutions into annular rising and descendingstreams at various elevations in said extracting chamber, the annular rising streams formed at each of said elevations being oi different diam- 1 eters but approximately concentric with, and separated from, each other, causing relatively heavy annular descending streams of the solutions to intersect and descend between separated rising annular streams at each of said elevations, allowing mixed light and heavy solutions to settle in approximately concentric annular settling zones between said elevations, causing descending heavy constituents to spread and flow laterally toward opposite sides of each 01' said annular settling zones. so as to divide each of said annular descending streams into two lateral streams of diil'erent diameters which ilow across two of said approximately concentric annular rising streams, the lateral streams from' one settling zone being merged with approxiannularirising streams formed atfieach-oi said elevations being separated from each other, and

causing annular descending streams of selective solvent to flow across and descendbetween separated rising streams at each 01' said elevations.

[7. In the .art of using selective solvents to cxtract naphthenic compounds from hydrocarbon.

liquids, the countercurrent process which comprises transmitting continuous streams of; the selective solvent and hydrocarbon liquid into diilt'erent portions-pf an extracting chamber, dividing resultant solutions into. numerous an-- nularrising streams and numerous descending "pounds atvarious elevations in saidextracting chamber, the annular rising streams iormedat each of said 'elevations being approximately concentric with, but separated from 3 each other, causing annular descending streams of said solvent and 'naphthenic compounds to intersect and descend between separated rising streams at each of. said elevations, allowing the resultant tract constituents of hydrocarbon liquids, the

countercurrent process which comprises transmitting continuous streams or selective solvent and hydrocarbon liquid into diflerent portions 01' mately concentric lateral streams from other I settling zones at the same elevation, two separated rlsing streams being formed between ad-' jacent settling zones, and each of said lateral streams being transmitted into one of the last mentioned rising streams before it merges into the lateral stream from another settling zone.

5. In the art of using selective solvents to extract constituents of hydrocarbon liquids, the

countercurrent process which comprises transmitting continuous streams oi the selective solvent and hydrocarbon liquid intodiflerent portions of an extracting chamber, causing result ant light and heavy solutions to advance step by step in opposite directions from one eleva-' tion to another, maintaining a series of separated but approximately concentric annular rising streams of successively increasing diameters at each of said elevations, spreading said rising anextracting chamber, causing the incoming streams or solvent hydrocarbon liquid to advance step by step from one plane to another through preliminary distributing zones, while spreading each incoming stream into a series of annular stream, the number of said annular streams being progressively increased as the incoming materials advance in said preliminary distributing zones, so as to gradually divide resultant ina coming solutions into a series of rising annular streams and a. series of relatively heavy annular descending streams, causing the rising solutions to advance step by step from one elevation to another while maintaining a plurality of separated annular rising streams at each 01' said elevations, and causing descending annular streams of the solutions to intersect and descend between separated annular rising streams at each of said elevations.

- EDDIE M. DONS."

' OSWALD G. MAURO. 

